New in factory sealed box Inferno Gen. 2 Spartan edition for V2 / M4! Free shipping available! The INFERNO Gen. 2 features a revolutionary single solenoid, independent poppet and nozzle design that sets a new standard for a drop in kit. Particularly, it is designed to solve the “open bolt problem”. It is a hybrid design which keeps the advantages of an open bolt system: easy tuning, no first round dry fire, efficiency, etc… and adds the simplicity of easier hop up tuning that closed bolt systems have traditionally offered. In addition, it further improves the efficiency over our previous systems by an estimated 10-15%. The Spartan Edition of the Inferno is programmed with the trigger! No FCU means no extra wiring and a much simpler interface, at the cost of not being able to physically see your settings.